DC vs. Stepper Motors

[AdamAReid]

I want to compare and contrast a DC Motor and a Stepper Motor. What are their primary uses, advantages, and disadvantages. The application I am looking at involves a drive system which is to provide a (relatively) constant torque of 10 N.m over it's range of opertion (0-50rpm output from a gearbox). I am trying to decide between the two motors.

Also, can anyone suggest where I can find information on motor controllers? I'd also like to know if such controllers can provide more constant torque output, and also provide data feedback such as speed, torque, etc.

Thanks.